Tolerance and physiological responses of Phragmites australis to water deficit
Tolerance and physiological responses of Phragmites australis to water deficit
复制标题
DOI：
10.1016/j.aquabot.2005.01.002
复制
发表时间：
2005-04-01
期刊：
影响因子：
1.8
通讯作者：
Brix, H
中科院分区：
文献类型：
--
作者：
Pagter, M;Bragato, C;Brix, H
芦荟(Phrigmites australis(Cav.)特林·前男友。斯图德。通过检测不同程度的水分亏缺对生长、光合作用和与水分胁迫相关的各种生理性状的影响，研究了不同水分胁迫水平对小麦生长的影响。单株在无限制供水条件下生长，与分别接受60%、30%、15%或5%的日需水量的植物组相比，水分亏缺导致新叶产量减少，落叶增加，平均叶大小减小，导致叶面积和单株叶生物量减少。叶片产量和叶片展开生长对水分供应非常敏感，当植物受到相当轻微的水分亏缺时，叶片产量和叶片展开生长都会减少。只有在严重胁迫下，叶片汁液中的渗透压和叶片中的脯氨酸浓度才显著增加，这表明在达到临界胁迫水平之前，渗透调节是次要的。在水分利用率很低之前，光合作用参数基本不受影响，这导致了CO2同化减少的主要原因是气孔关闭，而不是生化变化。水分胁迫对Rubisco的活性没有影响。CO2同化速率和气孔导度降低，内在水分利用效率(A/g(S))增加，表明水分胁迫下植物对CO2的有效利用。在受胁迫最严重的植物中，叶片的表观量子效率(Phi I)降低，这可能是由于气孔关闭后叶绿体中CO2摩尔分数的减少。南美白杨对水分亏缺的最初反应是叶面积减少，其余叶片保持良好的生理功能，直到受到严重胁迫。较高的水分利用效率和在严重水分胁迫下保持一定的光合作用能力，无疑有助于南美白杨在干旱条件下的生存。与其对洪水的良好适应能力相结合，南方藻似乎非常适合在水文周期波动较大的湿地地区生长。南美白杨在相当深的水中生长得很好，但也能耐受长时间的干旱，水分供应减少。(C)2005 Elsevier B.V.保留所有权利。
The water stress tolerance of Phragmites australis (Cav.) Trin ex. Steud. grown in the laboratory were investigated by examining effects of different levels of imposed water deficits on growth, photosynthesis and various physiological traits related to water stress. Individual plants were grown under conditions of unrestricted water supply and compared with groups of plants receiving 60, 30, 15 or 5% of previous daily water requirements, respectively.Water deficit was found to reduce the leaf area and the leaf biomass per plant due to decreased production of new leaves, increased leaf shedding and reduced average leaf size. Leaf production and leaf expansion growth were very sensitive to water availability and were reduced when plants were Subjected to fairly mild water deficit. Osmolality in sap expressed from leaves and the concentration of proline in leaves were only significantly increased in severely stressed plants, indicating that osmotic adjustment was of minor importance until a critical stress level was reached. Photosynthetic parameters were rather Unaffected until the water availability was very low and led to the assertion that reduced CO2 assimilation was mainly due to stomatal Closure and not biochemical changes. Water stress had no effect on the activity of Rubisco. The CO2 assimilation rate and stomatal conductance decreased in such a way that the intrinsic water use efficiency (A/g(s)) increased, indicating efficient CO2 utilization in water stressed plants. The apparent quantum yield (phi i) was reduced in leaves of the most stressed plants, probably due to a decrease in the CO2 molar fraction in the chloroplasts following stomatal closure.The initial response of P. australis to water deficit is a reduction in leaf area, the remaining leaves staying physiological rather well functioning until they are severely stressed. A high intrinsic water use efficiency and the ability to maintain some capacity for photosynthesis under severe water stress can undoubtedly contribute to the survival of P australis under dry conditions. Taken together with its well-developed adaptations to flooding, P australis seems very well adapted to grow in wetland areas with a widely fluctuating hydroperiod. P. australis grows very well in rather deep water, but can also tolerate extensive periods of drought with reduced availability of water. (c) 2005 Elsevier B.V. All rights reserved.